try updating your video drivers. What video card are you currently using?
Do a chdsk or check disk for errors on the hard drive.
Assuming your using Windows...
Go to My Computer
Right Click on the hard drive
Go to Properties
Go to the Tab "Tools"
Under Section "Error Checking"
Check Now
I had similar problems a week ago.
I had a Nvidia 6800 128 MB.
Once I launch any game, the screen would freeze but I still hear the game audio. Tried re-installing drivers, checking the hardware, etc.
After I replaced it, everything was fine.
I suggest replacing the video card. Go on newegg.com and find some decent video card. Like Keagle said, 6600 GT is good. Don't go for anything lower.
I stopped gaming so much so I bought a cheap 6200 for replacement and it's a horrible piece of junk.
ive tried two diffrent video cards and it still does it
what os are you using? XP, 98, Vista?
If you say 98, I will Laugh! But surprisingly some people still use it.
is CS the only application that is freezing?
Have you tried uninstalling and reinstalling the game? What about memory? How much memory does your XP machine have?